Magic, of course, consists of cheat codes to the universe. In some cases, that is quite literal. Some magicians turn into other things so they can, perhaps, spy on people (owls) or avoid ticket charges on trains (squat brown briefcases). But morphic magic requires passwords to get in and out.
Let it be a lesson to you to always note down passwords. Peter Cart, for example, once turned into a tree to spy on his neighbour and see if she had bought any new and interesting spells, and sort of forgot how to turn back. The spell was okay, but he kept getting the password just slightly wrong.
So there is a magician in London who looks like a tree. A tree that can move and do magic and even has a bit of a love life, thanks to a tolerant wife, but a tree nonetheless.
Also, an unclaimed black briefcase was once impounded by Metropolitan Railways and later incinerated because they couldn’t open it, and on the same night a magician from Fleet Street disappeared from her stately mansion. The connection has not been confirmed yet.
So remember the Boy Scouts motto – Always Be Prepared. Keep a pencil and notepaper handy, and turn into something that can read.